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| United States Patent |
5,334,265
|
|
Shalin
, et al.
|
August 2, 1994
|
Magnetic metal
Abstract
The magnetic material disclosed in a preferred embodiment of the invention
contains the following relative proportion of components, at. %:
______________________________________
at least one of the rare earth elements selected
12.0-17.0;
from the group consisting of Neodymium and
Praseodymium
at least one of the rare earth elements selected
0.1-5.0
from the group consisting of Dysprosium and
Terbium
at least one of the elements selected from the
0.5-4.0;
group consisting of Aluminum, Niobium, and
Chrome
at least one of the elements selected from the group
0.1-1.5;
consisting of Titanium, Hafnium, Zirconium,
Vanadium and Titanium
Cobalt 2.0-6.0
Boron 6.5-8.5
Uranium 0.05-1.5
Iron remainder
______________________________________
| Inventors:
|
Shalin; Rady E. (Moscow, SU);
Savich; Alexandr N. (Moscow, SU);
Kachanov; Evgeny B. (Moscow, SU);
Petrakov; Alexandr F. (Moskovskaya oblast, SU);
Piskorsky; Vadim P. (Moscow, SU);
Vevjurko; Alexandr I. (Moscow, SU);
Orlov; Vladislav K. (Moscow, SU);
Shingarev; Eduard N. (Moscow, SU);
Ivanov; Sergei I. (Moscow, SU);
Khaskin; Jury V. (Moscow, SU);
Buinovsky; Alexandr S. (Tomsk, SU);
Kondakov; Vladimir M. (Tomsk, SU)
|
| Assignee:
|
Aura System Inc. (El Segundo, CA)
|
| Appl. No.:
|
013766 |
| Filed:
|
February 4, 1993 |
| Current U.S. Class: |
148/302; 420/83; 420/121 |
| Intern'l Class: |
H01F 001/053 |
| Field of Search: |
148/301,302
420/83,121
|
References Cited
U.S. Patent Documents
| 4789521 | Dec., 1988 | Narasimhan et al. | 420/83.
|
| 4929275 | May., 1990 | Bogatin | 75/246.
|
Primary Examiner: Sheehan; John P.
Attorney, Agent or Firm: Ladas & Parry
Claims
We claim:
1. Magnetic material containing Fe-B-Co-R wherein R constitutes R.sub.1 and
R.sub.2, with R.sub.1 comprising at least one of the rare earth elements
selected from the group consisting of Neodymium (Nd) and Praseodymium
(Pr), with R.sub.2 comprising at least one of the rare earth elements
selected from the group consisting of Dysprosium (Dy) and Terbium (Tb),
and an admixture of M, which constitutes M.sub.1 and M.sub.2, M.sub.1
comprising at least one of the elements selected from the group consisting
of Aluminum (Al), Niobium (Nb), and Chromium (Cr), and M.sub.2 comprising
at least one of the elements selected from the group consisting of
Titanium (Ti), Hafnium (Hf), Zirconium (Zr), Vanadium (V), and Tantalum
(Ta), said magnetic material also containing Uranium (U) and having the
following relative proportion of components, in atomic %:
at least one of the rare earth elements selected from the group consisting
of Neodymium and Praseodymium 12.0-17.0;
at least one of the rare earth elements selected from the group consisting
of Dysprosium and Terbium 0.1-5.0;
at least one of the elements selected from the group consisting of
Aluminum, Niobium, and Chromium 0.5-4.0;
at least one of the elements selected from the group consisting of
Titanium, Hafnium, Zirconium, Vanadium, and Tantalum 0.1-1.5;
Cobalt 2.0-6.0
Boron 6.5-8.5
Uranium 0.05-1.5
Iron remainder.
2. The magnetic material, as claimed in claim 1 having the following
isotopic composition in % Uranium:
Uranium 238 99.7-99.9999
Uranium 235 0.0001-0.3.
3. The magnetic material as claimed in claim 1, wherein the admixture
M.sub.1 also contains Gallium (Ga).
4. The magnetic material, as claimed in claim 1, wherein the admixture
M.sub.2 also contains Scandium (Sc).
5. The magnetic material as claimed in claim 3 wherein the admixture
M.sub.2 also contains Scandium (Sc).
6. The magnetic material as claimed in claim 2 wherein the admixture
M.sub.1 also contains Gallium (Ga).
7. The magnetic material as claimed in claim 6 wherein the admixture
M.sub.2 also contains Scandium (Sc).
Description
FIELD OF THE INVENTION
The present invention pertains to special materials possessing special
physical characteristics and qualities, and, more specifically, pertains
to magnetic materials.
DESCRIPTION OF THE RELATED ART
The magnetic materials of the Fe-B-R and Fe-B-Co-R systems, possessing a
high level of magnetic energy (BH/2) max are presently well known and
widely utilized in electrical motors, generators, magnetic clutches, etc.
The above materials are also utilized in the various types of home
technology, in audio and video components, in computer peripherals, food
processors, coffee grinders, hair dryers, vacuum cleaners, refrigerators,
etc.
It should be noted, however, that the relatively low values of the coercive
force iHc characteristic of the listed materials restrict to some extent
the sphere of the their applicability. It is well known that with an
increase in temperature of a permanent magnet, its coercive force iHc will
decrease and the permanent magnet maybe completely demagnetized due to its
exposure to the increased temperature. If its coercive force iHc is
relatively high at room temperature, such demagnetizing influence by the
means of temperature will be insignificant.
Additionally, an increase in the value of the coercive force iHc of the
material, as pertains to the permanent magnets, allows a decrease in the
thickness of the permanent magnet while preserving the required
technological characteristics of the product. Therefore, in the case of
permanent magnets, an increase in iHc of the materials and the decrease in
the energy expenditures required for the production of 1 kg of magnets,
constitutes the current challenge of the time.
Specific energy expenditures incurred at the time of production of
permanent magnets composed of known materials from systems Fe-B-R and
Fe-B-Co-R are relatively high.
One known magnetic material is of the Fe-B-R system (Patent EP N 0134305
Aj). Within the known material R constitutes the sum total of R.sub.1 and
R.sub.2, while R.sub.1 is, at least, one of the rare earth elements
selected from the group of: Neodymium (Nd), Praseodymium (Pr), while
R.sub.2 is, at least, one of the rare earth elements selected from the
group of: Dysprosium (Dy), Terbium (Tb), Gadolinium (Gd), Holmium (Ho),
Erbium (Er), Thulium (Tm), and Ytterbium (Yb). The known material contains
an admixture of M, which is at least, one of the elements selected frown
the group of Chrome (Cr), Tantalum (Ta), Niobium (Nb), Aluminum (Al),
Vanadium (V), Tungsten (W), and Molybdenum (Mo).
The above elements contained in the known material are maintained in the
following composition (at. %): 0.05-5% R.sub.1, 12.5-20% R, 4-20% B and
the remaining iron (Fe) with admixtures of M, not in excess of 9%.
It is well known that the characteristic traits of the permanent magnet
material of the Fe-B-R system are determined by the quantity and size of
granules, by the specific magnetization and by the coercive force of the
core phase (R).sub.2 Fe.sub.14 B, as well as by the quantity, structure,
and composition of phases isolating the granules of the core phase
(R).sub.2 Fe.sub.14 B.
In order to obtain the peak traits of the magnetic material, as, for
example, (BH) max, operation temperature (Tmo), it is required that the
core phase (R).sub.2 Fe.sub.14 B be present in the material in a quantity
approaching 100%, that it has the optimal granule size, and the peak
possible values of specific magnetization and coercive force, while tile
phases isolating the core phase granules (R).sub.2 Fe.sub.14 B from each
other have to appear in the minimal quantity and be located along the
perimeter of the main core granules and be nonmagnetic.
Presence of such rare earth elements in the known material, as Dysprosium
(Dy), Terbium (Tb), Gadolinium (Gd), Holmium (Ho), etc. increases to a
greater or lesser extent the range of anisotrophy H.sub.A within the core
phase (NdR).sub.2 Fe.sub.14 B of the magnetic material which in turn
determines the increase of the coercive force iHc. However, the mutual
influence and interaction between the rare earth element ions and those of
iron causes the antiferromagnetic orientation of their magnetic aspects
which, in turn, causes a significant decrease of specific magnetization
and thus of residual induction of Br and (BH)max. In order to increase the
residual induction of Br additional, magnetically neutral elements of Cr,
Al, Nb, etc. are introduced into the magnetic material, while the contents
of Dysprosium (Dy) and Terbium (Tb) in the material, which increase the
magnet value, are being simultaneously decreased. The primary mechanism by
which the additional, above-named elements affect the coercive force is by
the means of formation of slightly magnetic phases enriched by Neodymium
and which isolate the granules of the core phase from each other. Some of
these elements, for example, Al, increase the wetability of the core phase
Nd.sub. 2 Fe.sub.14 B by the fluid phase, which, in turn, accelerates the
caking process, while producing the magnetic material. Since the size of
the core phase granules of the magnetic material is not uniform and
actually fluctuates within a range of 0.3-80 .mu.m, the material has a
relatively low coercive force iHc.
Based on the factors presented above, the magnetic traits of this material
are relatively low. Specifically:
the coercive force iHc=5-20 kOe
power generation (BH)max=5-38, 4 MGOe,
residual induction Br=5-12 KG.
It should be noted that the low values of the coercive force are associated
with the high values (BH)max and, vice-versa, the high values of (Bit)max
are associated with the lower values of iHc. In the case of optimal
inter-relationships of the components within the known magnetic material,
the coercive force iHc will be at least 10 kOe, (BH)max will be at least
20 MGOe, and the residual induction Br will be at least 9 KG. At
temperatures exceeding 80.degree.-100.degree. C. the known material
exhibits an abrupt decrease of its magnetic characteristics since it has a
low Curie temperature Tc=310.degree. C. This trait limits its
applicability within electrical mechanisms of high specific capacity. The
known material also exhibits relatively high energy expenditure at the
time of its manufacture due to the high stability of the ingot and the
caking temperature.
Another known magnetic material with a higher Curie temperature is the one
of the type Fe-B-Co-R (patent EP N 0106948 B.sub.1). Within the known
material, R constitutes the sum total of R.sub.1 and R.sub.2, while
R.sub.1 is, at least, one of the rare earth elements selected from the
group of Neodymium (Nd), Praseodymium (Pr) while R.sub.2 is at least one
of the heavy rare earth elements. The known material also incorporates the
admixture of M, which constitutes the sum total of M.sub.1 and M.sub.2,
while M.sub.1 is at least one of the elements selected from the group of
Aluminum (Al), Niobium (Nb), Chromium (Cr), and others, while M is, at
least, one of the elements selected from the group of Titanium (Ti),
Hafnium (Hf), Zirconium (Zr), Vanadium (V), Tantalum (T), etc. The
relative proportions of the above components within the magnetic material
are as follows: at. % 8-30% R=R.sub.1 +R.sub.2 ; 2-28% B, not to exceed
50% Co, and the remainder is iron (Fe) with admixtures of M=M.sub.1
+M.sub.2, not to exceed 12.5 %.
The presence of Cobalt (Co)in the magnetic material raises its Curie
temperature (Tc) and brings it to 750.degree. C. This allows the known
material to be utilized without a significant decrease of its magnetic
qualities within the temperatures from 120.degree.-160.degree. C. However
a high Cobalt (Co) content in the material produces a soft magnetic phase
enriched with Cobalt, which causes an abrupt decrease of the coercive
force iHc. In order to compensate for the decrease of the coercive force
iHc, the alloy is being formulated with intensified amount of rare earth
elements and Boron (B), which, in turn, brings about the decrease of
(BH)max. The latter is explained by relative decrease in the core phase
volume Nd.sub.2 Fe.sub.14 B. The average size of the core phase granules
within the known magnetic material ranges within 1-100 .mu.m, which
determines its low coercive force iHc. Additionally, the known material is
characterized by its relatively low technology, caused mostly by the
relatively high stability of ingot and the caking temperature, which, in
turn, causes the high degree of energy expenditures in the event of ingot
shredding and caking.
SUMMARY OF THE INVENTION
The basic goal of the present invention is to create magnetic material of a
chemical composition and of an at. % of the component contents that would
allow it to possess a high coercive force iHc value. This is achieved by
the optimization of the phase structures, which isolate the granules of
the main phase Nd.sub.2 Fe.sub.14 B, by the size of the main phase
granules, and by relatively low specific energy expenditures.
This goal has been achieved in the following fashion: the magnetic material
contains Fe-B-Co-R, within which R constitutes the sum total of R.sub.1
and R.sub.2, while R.sub.1 is, at least, one of the rare earth elements
selected from the group of Neodymium (Nd) and Praseodymium (Pr) while
R.sub.2 is at least one of the heavy rare earth elements selected from the
group of Dysprosium (Dy) and Terbium (Tb), and the admixture of M, which
constitutes the sum total of M.sub.1 and M.sub.2, while M.sub.1 is at
least one of the elements selected from the group of Aluminum (Al),
Niobium (Nb), Chromium (Cr), while M.sub.2 is at least, one of the
elements selected from the group of Titanium (Ti), Hafnium (Hf), Zirconium
(Zr), Vanadium (V), Tantalum (Ta), and also, according to the invention,
contains Uranium (U) with the following relative proportions of its
components, at. %:
at least one of the rare earth elements selected from the group of
Neodymium and Praseodymium 12.0-17.0;
at least one of the rare earth elements selected from the group of
Dysprosium and Terbium 0.1-5.0
at least one of the elements selected from the group of Aluminum, Niobium,
and Chrome 0.5-4.0;
at least one of the elements selected from the group of Titanium, Hafnium,
Zirconium, Vanadium, and Tantalum 0.1-1.5;
Cobalt 2.0-6.0
Boron 6.5-8.5
Uranium 0.05-1.5
Iron remainder
If it is required that the Uranium not emit radiation exceeding the natural
background radiation of cosmic rays and the radiation of isotopes
naturally present in the environment, it is imperative that the Uranium
(U) would have the following isotopic composition at. %
______________________________________
Uranium 238 99.7-99.9999
Uranium 235 0.0001-0.3
______________________________________
This kind of magnetic material, according to the invention, will be endowed
with high magnetic qualities, more specifically, will have a heightened
value of coercive force iHc of about 25 kOe with (BH)max=29-35 MGOe and
specific energy expenditures of 0.71-0.9.
The introduction of Uranium (U) into the magnetic material enhances the
isolating qualities of the intergranular phases of the type U-Fe-Co-R and
increases the anisotrophic field of the core phase (U+R).sub.2 Fe.sub.14
B. According to the invention, the x-ray diffraction analysis of the
magnetic material has shown that the Uranium ions come to partially
replace the ions of Neodymium within the lattice of the core phase and
Nd.sub.2 Fe.sub.14 B. However, it should be noted, that for the main part,
those ions are located in the intergranular Neodymium enriched phases,
which isolate the granules of the core phase.
The magnetic qualities of the Uranium compounds are determined by the
degree of localization of the Uranium ion electron 5f. In the combination
of Uranium (U) with Iron (Fe) the Uranium valence electrons move into the
"d" area of iron (Fe) until its full saturation thus decreasing the
magnetic aspects of the iron (Fe) atom. If the Uranium (U) contents within
the magnetic material is not in excess of 0.05 at. %, it will have no
effect for all intents and purposes on the magnetic aspect of the iron
(Fe) atoms or on the H.sub.A field of the core phase anisotrophy. When the
Uranium (U) contents is within the indicated range of 0.05-1.5 at. % the
Uranium ions, replacing the Neodymium ions within the lattice of the core
phase, increase the H.sub.A field anisotrophy and, consequently, the
coercive force iHc due to the partial localization of valence electrons
(5f electrons). Furthermore Uranium (U) reaching the lattice of the
intergranular phases of U-Fe-Co-R, lowers their Curie temperature (Tc) to
values substantially below room temperature. Therefore, the intergranular
phases of U-Fe-Co-B become paramagnetic when magnets made of this material
composition are operated, thus well securing the magnetic isolation of the
core phase granules and enhancing, in turn, the coercive force. In
addition, enriching the intergranular phases with Uranium causes the
decrease in the wetability of the core phase granules and consequently the
increase of the alloy embrittlement.
The magnetic material, according to the invention, is characterized by the
diminished specific energy expenditure at the time of the powder
preparation as well as at the time of its caking due to the enhanced
embrittlement of the fused material and its enhanced cakability at lower
temperatures of 1000.degree.-1100.degree. C.
If the Uranium (U) contents within the magnetic material exceeds 1.5 at. %
its concentration in the core phase Nd.sub.2 Fe.sub.14 B will reach the
level at which one can observe an abrupt decrease of the magnetic aspects
of iron (Fe) atoms as well as of the H.sub.A field anisotrophy and,
consequently, a decrease in the coercive force iHc due to the
delocalization of valence electrons (5f electrons). The alloy fusion with
Uranium exerts a positive effect on the magnetic material, and more
specifically, enhances its coercive force iHc, which is related also to
the decrease in the size of the core phase Nd.sub.2 Fe.sub.14 B granules
to the range of 4-6 .mu.m. It should be noted that the higher the
concentration of Uranium in the material, then the lower the average size
of the granules.
The natural Uranium is characterized by .alpha.-activity which is
determined mainly by the Uranium 235 isotope. At the Uranium isotopic
composition as indicated above and within the range of its values, the
magnitude of the dose of .alpha.-radiation exposure does not exceed the
natural background radiation of the cosmic rays and the radiation of the
isotopes naturally distributed in the environment.
Introduction of Scandium into the magnetic material increases its coercive
force iHc. This is connected to the changes within the fine structure of
the intergranular phases, isolating the core phase Nd.sub.2 Fe.sub.14 B
granules, since it is known that Scandium forms the ideal hard solutions
when combined with the rare earth elements. Additionally, the Scandium
ions assist in the localization of Uranium 5f electrons while partially
replacing Neodymium ions within (U+R).sub.2 Fe.sub.14 B phase, and,
consequently, enhance and heighten the H.sub.A field anisotrophy and the
coercive force iHc.
Introduction of Gallium (Ga) into the magnetic material increases its
coercive force iHc, for the following reasons. Gallium will replace Iron
within the core phase Nd.sub.2 Fe.sub.14 B, assuming positions 8j.sub.1
and 4c in the node, positions which are connected with the
antiferromagnetic interaction which causes, in tun, some increase in the
Curie temperature. However, the main positive consequence and effect from
the presence of Gallium stems from fact that by improving the core phase
Nd.sub.2 Fe.sub.14 B granule wetability by a liquid phase it facilitates
and enhances their magnetic isolation, thus, consequently, increasing the
coercive force iHc. In the event that the amount of Gallium (Ga) exceeds 4
at. % the magnetic material will exhibit H.sub.A field anisotrophy
decrease within the Nd.sub.2 Fe.sub.14 B core phase, and, consequently,
the decrease in the coercive force iHc.
BRIEF DESCRIPTION OF DRAWINGS
Other advantages and goals of this invention will become clearer and more
readily understandable on the basis of the following specific examples of
its implementation and its charts which show:
FIG. 1 table demonstrating the relationship between coercive force iHc and
Uranium (U) content;
FIG. 2 table demonstrating the relationship between coercive force iHc and
the average granule size;
FIG. 3 table demonstrating the relationship between coercive force iHc and
Scandium (Sc) contents;
FIG. 4 table demonstrating the relationship between coercive force iHc and
Gallium (Ga) content.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The magnetic material as represented in this invention contains
Fe-B-Co-U-R-M. R constitutes the sum total of R.sub.1 and R.sub.2, while
R.sub.1 is, at least, one of the rare earth elements selected from the
group of Neodymium (Nd) and Praseodymium (Pr) while R.sub.2 is at least
one of the rare earth elements selected from the group of Dysprosium (Dy)
and Terbium (Tb). The admixture of M, constitutes the sum total of M.sub.1
and M.sub.2, while M.sub.1 is at least one of the elements selected from
the group of Aluminum (Al), Niobium (Nb), Chromium (Cr), and Gallium (Ga)
while M.sub.2 is, at least, one of the elements selected from the group of
Titanium (Ti), Hafnium (Hf), Zirconium (Zr), Vanadium (V), Tantalum (Ta),
and Scandium (Sc). The magnetic material indicated above contains the
above components in the following relative proportions of at. %:
______________________________________
Neodymium and/or Praseodymium
12.0-17.0
Dysprosium and/or Terbium
0.1-5.0
Aluminum and/or Niobium, and/or
0.5-4.0
Gallium, and/or Chrome
Titanium and/or Hafnium, and/or
0.1-1.5
Zirconium, and/or Vanadium, and/or
Tantalum, and/or Scandium
Cobalt 2.0-6.0
Boron 6.5-8.5
Uranium 0.05-1.5
Iron remainder
______________________________________
Uranium introduced into the magnetic matter as described in this invention
has the following isotopic composition in at. %:
______________________________________
Uranium 238 99.7-99.9999
Uranium 235 0.0001-0.3
______________________________________
Its dosage magnitude of .alpha.-radiation exposure does not exceed the
natural background radiation of the cosmic rays and the radiation of the
isotopes naturally distributed in the environment. The cumulative content
of the elements in the magnetic material is as follows: Neodymium and/or
Praseodymium, Dysprosium and/or Terbium and Uranium are in tile range of
15-17.6 at. % At the same time the cumulative content of the elements
listed below in the magnetic material is as follows:
at least one element selected from tile group of Aluminum (Al), Niobium
(Nb), Chrome (Cr), Gallium (Ga), and
at least one element selected from the group of Titanium (Ti), Hafnium
(Hf), Zirconium (Zr), Vanadium (V), Tantalum (Ta), and Scandium (Sc) are
within the range of 0.6-4.5 at. %
The magnetic material according to this invention is obtained in the
following manner.
As a first step, fusion is obtained in a vacuum induction oven with an
Argon atmosphere maintained at a pressure of 300 mm Hg. The composition of
the material produced corresponds to the magnetic materials which are
presented in Table No. 1. Boron is introduced into the fusion as an alloy
Fe-10 mass % B (at. %). The obtained alloy is transferred into a
water-cooled, copper ingot mold and an ingot is thus made. This ingot is
initially grossly fragmented into particles smaller than 500 .mu.m and
then pulverized in a vibrational ball grinder into particles that are 1-5
.mu.m in size. The powder thus obtained is then placed into a magnetic
field with a force of 10 kOe in order to create magnetic texturing while
being molded under a pressure of 0.1-5 t/cm.sup.2. The pressed material
obtained is then caked at a temperature 1000.degree.-1200.degree. C. with
subsequent heat treatment of the cake at temperatures between
400.degree.-1000.degree. C.
Examples of the magnetic material obtained by the procedure outlined in
this invention are presented below.
EXAMPLE 1
Magnetic material Fe-5Co-7-B-13, 5Nd-1, 5Dy-1Al-O, 5Ti-O, 1So-xU is
obtained as follows.
A fusion is obtained in a vacuum induction oven with an Argon atmosphere
maintained at a pressure of 300 mm Hg. The composition of the material
produced corresponds to the magnetic material presented in Table No. 1 (3,
27, 28, 29, 31, 32, 39). An ingot is obtained from the fusion as specified
above which is subsequently fragmented and pulverized into particles of
3-4 .mu.m in size. The pulverized particles are placed into a magnetic
field with a force not less than 10 kOe while being molded under a
pressure of 0.4 t/cm.sup.2. The material thus obtained is caked at a
temperature of 1030.degree.-1130.degree. C. over a period of 2 hours with
subsequent heat treatment of the cake at temperatures between
550.degree.-910.degree. C.
The magnetic traits of this material as well as the specific amounts of
energy expenditure are listed in Table 1. The effect of Uranium on the
coercive force intensity iHc can be seen in the Chart which appears in
FIG. 1. Analysis of the curve displayed indicates that an abrupt increase
of the coercive force iHc up to 23 kOe takes place when the content of
Uranium in the magnetic material is within the range of x=0.05-0.2 at. %
This is caused by two factors. First, by the decrease in the average size
of the core phase Nd.sub.2 Fe.sub.14 B granules due to the increase in the
Uranium content within the magnetic material (see FIG. 2) and, secondly,
due to the partial replacement of Neodymium ions by those of Uranium while
maintaining the localization of 5f Uranium ion electrons and enhancing the
anisotrophic H field. As FIG. 2 indicates; the granule size is
monotonously decreasing, proportionally to the increase of the Uranium
content, while in the range of x=0.2-1.5 at. % (FIG. 1) the coercive force
value iHc is virtually lost; it stands at 23.1 kOe and is independent of
the Uranium content. This virtual stability of the iHc value is determined
by two contradictory processes. On the one hand, there is an increase in
the Uranium content within the core phase, which, in turn, brings about
the partial delocalization of its 5f electrons and consequently the
decline of the anisotrophic field of the magnetic core phase Nd.sub.2
Fe.sub.14 B. On the other hand, the decrease in granule size causes an
increase in the iHc; however, this is mainly obtained due to the decrease
in the number of centers in which reverse polarity is generated. With the
increase of concentration x>1.5 at/% U, the delocalization of 5f Uranium
electrons within the core phase causes an abrupt decrease in the
anisotrophic field and consequently the decrease in the coercive force
iHc.
EXAMPLE 2
The magnetic material: Fe-5Co-7B-13, 5Nd-O,5U-1, 5Dy-1Al-O,5Ti-xSc is
obtained in the following fashion.
A fusion is obtained in a vacuum induction oven with an Argon atmosphere
maintained at a pressure of 300 mm Hg. The composition of the material
produced corresponds to the magnetic material presented in Table No. 1 (3,
16, 63, 64, 65). An ingot is obtained from the fusion as specified above
which is subsequently fragmented and pulverized into particles of 3 .mu.m
in size. The pulverized particles are placed into a magnetic field with a
force not less than 10 kOe while being molded under a pressure of 0.8
t/cm.sup.2. The material thus obtained is caked at a temperature of
1070.degree. C. over a period of 2 hours with subsequent heat treatment of
the cake at temperatures between 560.degree.-910.degree. C.
The magnetic traits of this material as well as the specific amounts of
energy expenditure are listed in Table 1.
The effect of Scandium content on the coercive force intensity iHc can be
seen in tire Chart which appears in FIG. 3. Analysis of the curve
displayed indicates that an abrupt increase of the coercive force iHc up
to 23 kOe takes place when the content of Scandium in the magnetic
material is within the range of x=0.03-0.1 at. %. This is due to the fact
that the presence of Scandium ions within the core phase Nd.sub.2
Fe.sub.14 B causes delocalization of 5f Uranium electrons. Additionally,
since Scandium forms hard solutions with all of the rare earth metals it
brings about a change in structure of all of the intergranular phases thus
decreasing the number of centers in which the reverse magnetic force may
be generated. The increase of Scandium content level to greater than 1.5
at. % causes the decrease of iHc due to the decrease in the anisotrophic
field of the core phase Nd.sub.2 Fe.sub.14 B. Scandium exerts a positive
influence on the coercive force only when in combination with such
elements as U and Dy.
EXAMPLE 3
The magnetic material: Fe-5Co-7B-13, 5Nd-O,5U-1, 5Dy-1Al-O,1Sc-xGa is
obtained in the following fashion.
A fusion is obtained in a vacuum induction oven with an Argon atmosphere
maintained at a pressure of 300 mm Hg. The composition of the material
produced corresponds to the magnetic material presented in Table No. 1
(49, 66-71). An ingot is obtained from the fusion as specified above which
is subsequently fragmented and pulverized into particles of 3 .mu.m in
size. The pulverized particles are placed into a magnetic field with a
force not less than 10 kOe while being molded under a pressure of 0.8
t/cm.sup.2. The material thus obtained is caked at a temperature of
1000.degree.-1100.degree. C. over a period of 2 hours with subsequent heat
treatment of the cake at temperatures between 490.degree.-920.degree. C.
The magnetic traits of this material as well as the specific amounts of
energy expenditure are listed in Table 1.
The effect of Gallium content on the coercive force intensity iHc appears
in FIG. 4. The nature of iHc curve behavior with a change in x is similar
to the nature of changes in the coercive force behavior that occur with a
change in the content of Uranium or Scandium.
The abrupt increase of the coercive force iHc up to 23.2 kOe takes place
when the content of Gallium is within the range of x=0.03-1.0 at. % and is
related to the increase in the anisotrophic field of the core phase with a
partial replacement of Iron by Gallium. Additionally, Gallium enable a
better magnetic isolation of the core phase granules at the time of caking
since it enhances the core phase Nd.sub.2 Fe.sub.14 B granule wetability
with a liquid phase. The abrupt decrease of the coercive force iHc at x>4
at. % Ga is related to a number of factors. First of all, the Curie
temperature (Tc) of the core phase (and therefore also of the anisotrophic
constant) begins to decrease rapidly due to the fact that Iron is being
replaced by Gallium (Ga). Secondly, the mutual interaction between the
Iron and the rare earth element grids decreased due to the fact that
Gallium is not magnetized.
Industrial Applications
The most successful application of this invention is in the realm of
electronics and electrical technology and engineering.
The magnetic material presented in this invention, at the specific
expenditures in the range of 0.71-0.9 has residual induction Br=10.5-25.5
kG, coercive force iHc=14-25.1 kOe, energy generation (BH)max=29.5-36.0
MGOe and maybe operated at temperatures up to 180.degree.-250.degree. C.
TABLE 1-1
__________________________________________________________________________
magnetic properties
(BH) max
Specific
Compositions iHc Br (MG energy
No.
(at. %) (kOe)
(kG)
Oe) expenditures
__________________________________________________________________________
1 Fe-5Co-7B-11Nd-0.5U-6Dy-1Al-0.5Ti-0.1Sc
20.0
10.5
26.7 0.80
2 Fe-5Co-7B-12Nd-0.5U-2.5Dy-1Al-0.5Ti-0.1Sc
23.0
11.0
29.4 0.82
3 Fe-5Co-7B-13.5Nd-0.5U-1.5Dy-1Al-0.5Ti-0.1Sc
23.0
11.4
31.5 0.82
4 Fe-5Co-7B-15Nd-0.5U-0.8Dy-1Al-0.5Ti-0.1Sc
20.8
11.1
29.9 0.83
5 Fe-5Co-7B-17Nd-0.5U-0.1Dy-1Al-0.5Ti-0.1Sc
20.5
11.0
29.4 0.81
6 Fe-5Co-7B-18Nd-0.1U-0.1Dy-1Al-0.5Ti-0.1Sc
20.4
10.8
28.3 0.95
7 Fe-5Co-7B-13.5Pr-0.5U-1.5Dy-1Al-0.5Ti-0.1Sc
23.8
11.2
30.4 0.82
8 Fe-5Co-7B-14Nd-0.5U-1.5Dy-1Al-0.5Ti-0.1Sc
23.5
11.3
31.0 0.81
9 Fe-5Co-7B-11Pr-0.5U-5Dy-1Al-0.5Ti-0.1Sc
20.5
10.5
26.7 0.81
10 Fe-5Co-7B-12Pr-0.5U-2.6Dy-1Al-0.5Ti-0.1Sc
23.0
11.0
29.4 0.81
11 Fe-5Co-7B-13.5Pr-0.5U-1.6Dy-1Al-0.5Ti-0.1Sc
23.1
11.5
31.6 0.82
12 Fe-5Co-7B-17Pr-0.4U-0.1Dy-1Al-0.5Ti-0.1Sc
20.5
11.0
29.4 0.81
13 Fe-5Co-7B-18Pr-0.1U-0.1Dy-1Al-0.5Ti-0.1Sc
20.1
10.8
28.3 0.95
14 Fe-5Co-7B-17Nd-0.5U-0.5Dy-1Al-0.5Ti-0.1Sc
19.8
11.1
29.9 0.75
15 Fe-5Co-7B-15.5Nd-0.5U-0.1Dy-1.5Al-0.5Ti-0.2Sc
20.7
11.6
32.6 0.84
__________________________________________________________________________
TABLE 1-2
__________________________________________________________________________
magnetic properties
(BH) max
Specific
Compositions iHc Br (MG energy
N0.
(at. %) (kOe)
(kG)
Oe) expenditures
__________________________________________________________________________
16 Fe-5Co-7B-13.5Nd-0.5U-1.5Dy-1Al-0.5Ti-0.2Sc
23.0
11.4
31.5 0.83
17 Fe-5Co-7B-12.5Nd-0.5U-2.5Dy-0.5Al-0.5Ti-0.2Sc
23.0
11.0
29.5 0.84
18 Fe-5Co-7B-12Nd-0.1U-5Dy-0.5Al-0.5Ti-0.07Sc
21.2
11.0
29.5 0.89
19 Fe-5Co-7B-11Nd-0.1U-6DY-0.5Al-0.1Ti-0.07Sc
22.3
10.7
27.8 0.90
20 Fe-5Co-7B-12Nd-0.5U-2.5Tb-0.5Al-0.5Ti-0.3Sc
23.0
11.0
29.4 0.82
21 Fe-5Co-7B-12Nd-0.5U-1.5Dy-0.5Al-0.5Ti-0.2Sc
22.8
11.0
29.6 0.81
22 Fe-5Co-7B-17Nd-0.5U-0.05Tb-0.5Al-0.5Ti-0.1Sc
19.9
11.1
29.8 0.75
23 Fe-5Co-7B-15.5Nd-0.5U-0.1Tb-0.5Al-0.5Ti-0.2Sc
20.8
11.6
32.7 0.84
24 Fe-5Co-7B-13.5Nd-0.5U-1.5Tb-0.5Al-0.5Ti-0.2Sc
23.0
11.4
31.5 0.87
25 Fe-5Co-7B-12Nd-0.2U-5Tb-0.5Al-0.5Ti-0.07Sc
21.2
11.0
29.5 0.89
26 Fe-5Co-7B-11Nd-0.1U-6Tb-0.5Al-0.1Ti-0.7Sc
22.3
10.7
27.6 0.90
27 Fe-5Co-7B-13.5Nd-0.03U-1.5Dy-1Al-0.5Ti-0.2Sc
19.8
11.5
32.1 0.99
28 Fe-5Co-7B-13.5Nd-0.05U-1.5Dy-1Al-0.5Ti-0.4Sc
21.0
11.4
31.5 0.90
29 Fe-5Co-7B-13.5Nd-0.7U-1.5Dy-1Al-0.5Ti-0.1Sc
23.1
11.3
31.0 0.80
30 Fe-5Co-6.6B-14.5Nd-0.05U-0.1Dy-0.5Al-0.1Ti-0.05Sc-
14.0
12.5
36.0 0.90
0.05Ga
__________________________________________________________________________
TABLE 1-3
__________________________________________________________________________
magnetic properties
(BH) max
Specific
Compositions iHc Br (MG energy
N0.
(at. %) (kOe)
(kG)
Oe) expenditures
__________________________________________________________________________
31 Fe-5Co-7B-13.5Nd-1.5U-1.5Dy-1Al-0.5Ti-0.07Sc
22.5
11.0
29.6 0.71
32 Fe-5Co-7B-13.5Nd-2U-1.5Dy-1Al-0.5Ti-0.07Sc
19.5
10.5
26.7 0.68
33 Fe-1Co-7B-13.5Nd-0.5U-1.5Dy-1Al-0.5Ti-0.2Sc
23.2
11.4
29.2 0.83
34 Fe-2Co-7B-13.5Nd-0.5U-1.5Dy-1Al-0.5Ti-0.1Sc
23.2
11.4
31.5 0.82
35 Fe-6Co-7B-13.5Nd-0.5U-1.5Dy-1Al-0.5Ti-0.1Sc
21.5
11.4
31.5 0.84
36 Fe-8Co-7B-13.5Nd-0.5U-1.5Dy-1Al-0.5Ti-0.1Sc
19.0
11.0
29.3 0.81
37 Fe-5Co-6B-13.5Nd-0.5U-1.5Dy-1Al-0.5Ti-0.1Sc
20.0
10.8
28.3 0.82
38 Fe-5Co-6.5B-13.5Nd-0.5U-1.5Dy-1Al-0.5Ti-0.1Sc
21.5
11.2
30.4 0.85
39 Fe-5Co-7B-13.5Nd-0.5U-1.5Dy-1Al-0.5Ti-0.1Sc
23.0
11.4
31.5 0.84
40 Fe-5Co-8.5B-13.5Nd-0.5U-1.5Dy-1Al-0.5Ti-0.1Sc
24.5
11.1
29.9 0.82
41 Fe-5Co-10B-13.5Nd-0.5U-1.5Dy-1Al-0.5Ti-0.1Sc
25.1
10.5
26.7 0.82
42 Fe-5Co-7B-12Nd-0.5U-5Dy-0.1Al-0.5Ti-0.1Sc
19.8
11.3
31.0 0.84
43 Fe-5Co-7B-12Nd-0.5U-5Dy-0.5Al-0.1Ti-0.06Sc
21.2
11.0
29.6 0.84
__________________________________________________________________________
TABLE 1-4
__________________________________________________________________________
magnetic properties
(BH) max
Specific
Compositions iHc Br (MG energy
N0.
(at. %) (kOe)
(kG)
Oe) expenditures
__________________________________________________________________________
44 Fe-5Co-7B-13.5Nd-0.5U-1.5Dy-3Al-0.5Ti-0.1Sc
22.5
11.2
30.4 0.83
45 Fe-5Co-7B-16Nd-0.5U-1.5Dy-4Al-0.4Ti-0.1Sc
21.8
11.0
29.4 0.84
46 Fe-5Co-7B-16Nd-0.5U-0.1Dy-5Al-0.1Ti-0.1Sc
22.1
10.7
27.8 0.83
47 Fe-5Co-7B-13.5Nd-0.5U-1.5Dy-1Nb-0.5Ti-0.1Sc
22.5
11.4
31.5 0.83
48 Fe-5Co-7B-13.5Nd-0.5U-1.5Dy-1Cr-0.5Ti-0.1Sc
23.0
11.2
30.4 0.83
49 Fe-5Co-7B-13.5Nd-0.5U-1.5Dy-0.5Ti-0.1Sc-1Ga
23.2
11.4
31.5 0.84
50 Fe-5Co-7B-13.5Nd-0.5U-1.5Dy-1Al-0.5Nb-0.5Cr-0.5Ti-
22.5
11.1
29.9 0.84
0.1Sc-1Ga
51 Fe-5Co-7B-13.5Nd-0.5U-1.5Dy-1Al-0.05Ti-0.1Sc
19.9
11.5
32.1 0.82
52 Fe-5Co-7B-13.5Nd-0.5Nd-0.5U-1.5Dy-1Al-0.1Ti-0.1Sc
21.5
11.4
31.5 0.82
53 Fe-5Co-7B-13.5Nd-0.5U-1.5Dy-1Al-1.5Ti-0.1Sc
23.2
11.0
29.4 0.83
54 Fe-5Co-7B-13.5Nd-0.5U-1.5Dy-1Al-2Ti-0.1Sc
23.5
10.7
27.8 0.84
55 Fe-5Co-7B-13.5Nd-0.5U-1.5Dy-1Al-0.5Hf-0.2Sc
22.3
11.2
30.4 0.82
56 Fe-5Co-7B-13.5Nd-0.5U-1.5Dy-1Al-0.5Zr-0.2Sc
22.5
11.2
30.4 0.82
57 Fe-5Co-7B-13.5Nd-0.5U-1.5Dy-1Al-0.5Hf-0.5Zr-0.5Sc
22.8
11.2
30.4 0.82
__________________________________________________________________________
TABLE 1-5
__________________________________________________________________________
magnetic properties
(BH) max
Specific
Compositions iHc Br (MG energy
No.
(at. %) (kOe)
(kG)
Oe) expenditures
__________________________________________________________________________
58 Fe-5Co-7B-13.5Nd-0.5U-1.5Dy-1Al-0.5V-1.2Sc
22.9
11.2
30.5 0.84
59 Fe-5Co-7B-13.5Nd-0.5U-1.5Dy-1Al-0.5Ta-0.1Sc
23.0
11.1
30.4 0.82
60 Fe-5Co-7B-13.5Nd-0.5U-1.5Dy-1Al-0.1Ti-0.1Hf-0.1Zr-
23.0
11.2
30.3 0.82
0.1V-0.1Ta-0.1Sc
61 Fe-5C0-7B-13.5Nd-0.5U-1.5Dy-1Al-0.1Ti-0.1Hf-0.1V-
18.8
11.2
30.1 0.88
0.03Sc
62 Fe-5Co-7B-13.6Nd-0.5U-1.5Dy-1Al-0.15Ti-0.1V-0.05Sc
20.9
11.2
30.1 0.86
63 Fe-5Co-7B-13.5Nd-0.5U-1.5Dy-1Al-0.15Ti-0.5Sc
21.0
11.2
30.4 0.82
64 Fe-5Co-7B-13.6Nd-0.5U-1.5Dy-1Al-0.2Ti-1.5Sc
20.4
11.1
30.1 0.82
65 Fe-5Co-7B-13.5Nd-0.5U-1.5Dy-1Al-1.15Ti-2Sc
19.0
11.0
29.5 0.82
66 Fe-5Co-7B-13.5Nd-0.5U-1.6Dy-1Al-0.05Sc-0.03Ga
19.3
11.2
29.0 0.83
67 Fe-5Co-7B-13.5Nd-0.5U-1.6Dy-1Al-0.05Sc-0.05Ga
20.8
11.1
29.5 0.83
68 Fe-5Co-7B-13.5Nd-0.5U-1.6Dy-1Al-0.05Sc-0.5Ga
21.0
11.0
29.7 0.82
69 Fe-5Co-7B-13.5Nd-0.5U-1.6Dy-1Al-0.05Sc-1Ga
21.4
11.0
29.8 0.82
70 Fe-5Co-7B-13.5Nd-0.5U-1.6Dy-0.5Al-0.5V-0.05Sc-4Ga
20.9
11.0
29.5 0.82
71 Fe-5Co-7B-13.5Nd-0.5U-1.6Dy-0.5Al-0.05Sc-5.5Ga
19.7
11.1
27.0 0.82
__________________________________________________________________________
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